1. Field of the Invention
The present invention relates to a wireless station and a frame constructing method and a frame reading method thereof. More specifically, the present invention relates to a wireless station and a frame constructing method and a frame reading method thereof according to information related to the axes defining the frame.
2. Descriptions of the Related Art
In the conventional wireless networks, stations (i.e. a base station (BS), a relay station (RS), and a mobile station (MS)) are configured to transmit data according to a mapping message field defined in a frame. The aforementioned data is a plurality of bursts, or called allocations, in the frame. A station which has received the frame extracts the desired bursts according to the mapping message field in the frame. In the IEEE 802.16 standard, the MAP defined in a frame plays the role of the aforementioned mapping message field.
The mapping message field records the arrangement of the radio resource of the frame. The aforementioned radio resource includes frequency bands and time symbols (such as Orthogonal Frequency-Division Multiple Access (OFDMA) symbols in the IEEE 802.16 standard). Please refer to FIG. 1 for a schematic view of a frame 1. The frame 1 comprises a mapping message field 100 and a plurality of bursts 102, 104, 106, 108, 110, 112. The horizontal axis of the frame 1 represents time symbols, while the vertical axis of the frame 1 represents frequency band.
Conventionally, an identity of a destination station of the burst and four parameters are recorded in the mapping message field for each of the bursts 102, 104, 106, 108, 110, 112, so a station that receives the frame 1 knows the resource allocation of the burst. The four parameters are the OFDMA symbol offset, frequency band offset, the number of the OFDMA symbols (i.e. time symbols), and the number of the frequency bands. Specifically, the OFDMA symbol offset and the frequency band offset are configured to define a start of a burst, while the numbers of time symbols (i.e. the OFDMA symbols) and the number of frequency bands are configured to define a size of the burst in the frame. In other words, the four parameters can be treated as two 2D coordinates, wherein one of the 2D coordinates represents a start of a burst, while the other 2D coordinate represents a size of the burst.
For example, a start of the burst 102 of the frame 1 is defined by the 2D coordinate (OFDMA symbol offset, frequency band offset) of the point 101 in the mapping message field 100, and the size of the burst 102 is defined by the number of OFDMA symbols L1 and the number of the frequency bands W1. Thus, an identity of the destination station to receive the burst 102, the 2D coordinate of the point 101, and the 2D coordinate (L1, W1) are recorded in the mapping message field 100. Thereby, the destination station (i.e. a station whose identity is equal to the identity recorded in the mapping message field 100) can acquire the resource allocation information of the burst 102 according to the 2D coordinate of the point 101 and the 2D coordinate (L1, W1) recorded in the mapping message field 100 and then extract the burst 102 according to the resource allocation information of the burst 102.
Similarly, a start of the burst 104 is represented by the 2D coordinate (OFDMA symbol offset, frequency symbol band) of the point 103 of the burst 104 in the mapping message field 100 and the size of the burst 104 is represented by the number of OFDMA symbols L2 and the number of frequency bands W2. A start of the burst 106 is represented by the 2D coordinate (OFDMA symbol offset, frequency band offset) of the point 105 of the burst 106 in the mapping message field 100 and the size of the burst 106 is defined by the number of OFDMA symbols L3 and the number of frequency bands W3. A start of the burst 108 is represented by the 2D coordinate (OFDMA symbol offset, frequency band offset) of the point 107 of the burst 108 in the mapping message field 100 and the size of the burst 108 is represented by the number of OFDMA symbols L4 and the number of frequency bands W4. A start of the burst 110 is represented by the 2D coordinate (OFDMA symbol offset, frequency symbol offset) of the point 109 of the burst 110 in the mapping message field 100 and the size of the burst 110 is represented by the number of OFDMA symbols L5 and the number of frequency bands W5. A start of the burst 112 is represented by the 2D coordinate (OFDMA symbol offset, frequency band offset) of the point 111 of the burst 112 in the mapping message field 100 and the size of the burst 112 is represented by the number of OFDMA symbols L6 and the number of frequency bands W6. Thereby, a station can acquire the resource allocation information of the burst 104, 106, 108, 110, 112 and then extract the burst 104, 106, 108, 110, 112 according to the resource allocation information of the burst 104, 106, 108, 110, 112.
A conventional wireless network based on the IEEE 802.16 standard needs four parameters to represent the resource allocation information of each burst, which introduce extra loads in transmission and thus increases extra costs of the wireless network.
In summary, how to represent resource allocation information of each burst clearly and not increase the extra loads in transmission and the extra costs of the wireless network is still an objective for the industry to endeavor.